RESUMO
PURPOSE: To determine corneal cross-linking (CXL) efficacy and chromophore penetration after excimer laser-assisted patterned de-epithelialization. METHODS: Two-hundred-twenty porcine eyes were de-epithelialized ex vivo, either fully (mechanical; n = 88) or patterned (excimer laser; n = 132). Consecutively, corneas were impregnated with hypo- or hyperosmolar riboflavin (RF; n = 20, RF-D; n = 40, respectively) or water-soluble taurine (WST11; n = 40, and WST-D; n = 40, respectively), or kept unimpregnated (n = 80). Sixty corneas were subsequently irradiated, inducing CXL, with paired contralateral eyes serving as controls. Outcome measurements included strip extensiometry to assess CXL efficacy, and spectrophotometry and fluorescence microscopy to determine stromal chromophore penetration. RESULTS: All tested chromophores induced significant CXL (p < 0.001), ranging from 7.6% to 14.6%, with similar stiffening for all formulations (p = 0.60) and both de-epithelialization methods (p = 0.56). Light transmittance was significantly lower (p < 0.001) after full compared with patterned de-epithelialization. Stromal chromophore penetration was comparable between fully and patterned de-epithelialized samples, with full penetration in RD and RF-D samples and penetration depths measuring 591.7 ± 42.8 µm and 592.9 ± 63.5 µm for WST11 (p = 0.963) and 504.2 ± 43.2 µm and 488.8 ± 93.1 µm for WST-D (p = 0.669), respectively. CONCLUSIONS: Excimer laser-assisted patterned de-epithelialization allows for effective CXL. Stromal chromophore concentration is, however, reduced, which may have safety implications given the need for sufficient UVA attenuation in RF/UVA CXL. The different safety profile of near-infrared (NIR) may allow safe WST11/NIR CXL even with reduced stromal chromophore concentration values. In vivo studies are needed to evaluate the benefits and further assess safety of excimer laser-assisted patterned de-epithelialization for corneal CXL.
Assuntos
Substância Própria , Lasers de Excimer , Animais , Colágeno/farmacologia , Córnea/cirurgia , Substância Própria/cirurgia , Reagentes de Ligações Cruzadas/farmacologia , Humanos , Lasers de Excimer/uso terapêutico , Fármacos Fotossensibilizantes/farmacologia , Fármacos Fotossensibilizantes/uso terapêutico , Riboflavina/farmacologia , Riboflavina/uso terapêutico , Suínos , Raios UltravioletaRESUMO
Effective treatment of advanced metastatic disease remains the primary challenge in the management of inoperable pancreatic cancer. Current therapies such as oxaliplatin (OxPt)-based chemotherapy regimens (FOLFIRINOX) provide modest short-term survival improvements, yet with significant toxicity. Photodynamic therapy (PDT), a light-activated cancer therapy, demonstrated clinical promise for pancreatic cancer treatment and enhances conventional chemotherapies with non-overlapping toxicities. This study investigates the capacity of neoadjuvant PDT using a clinically-approved photosensitizer, benzoporphyrin derivative (BPD, verteporfin), to enhance OxPt efficacy in metastatic pancreatic cancer. Treatment effects were evaluated in organotypic three-dimensional (3D) cultures, clinically representative models that bridge the gap between conventional cell cultures and in vivo models. The temporally-spaced, multiparametric analyses demonstrated a superior efficacy for combined PDT+OxPt compared to each monotherapy alone, which was recapitulated on different organotypic pancreatic cancer cultures. The therapeutic benefit of neoadjuvant PDT to OxPt chemotherapy materialized in a time-dependent manner, reducing residual viable tissue and tumor viability in a manner not achievable with OxPt or PDT alone. These findings emphasize the need for intelligent combination therapies and relevant models to evaluate the temporal kinetics of interactions between mechanistically-distinct treatments and highlight the promise of PDT as a neoadjuvant treatment for disseminated pancreatic cancer.
RESUMO
The ability of tumor cells to adapt to therapeutic regimens by activating alternative survival and growth pathways remains a major challenge in cancer therapy. Therefore, the most effective treatments will involve interactive strategies that target multiple nonoverlapping pathways while eliciting synergistic outcomes and minimizing systemic toxicities. Nanoliposomal irinotecan is approved by the FDA for gemcitabine-refractory metastatic pancreatic cancer. However, the full potential of irinotecan treatment is hindered by several cancer cell survival mechanisms, including ATP-binding cassette G2 (ABCG2) transporter-mediated irinotecan efflux from cells. Here, we demonstrate that benzoporphyrin derivative-based photodynamic therapy (PDT), a photochemical cytotoxic modality that activates the apoptotic pathway, reduced ABCG2 expression to increase intracellular irinotecan levels in pancreatic cancer. Moreover, we show that PDT inhibited survivin expression. Although PDT potentiated irinotecan treatment, we also demonstrate that irinotecan reduced the tumoral expression of monocarboxylate transporter 4, which was upregulated by PDT. Notably, using orthotopic xenograft models, we demonstrate that combination of single low-dose PDT and a subclinical dose of nanoliposomal irinotecan synergistically inhibited tumor growth by 70% for 3 weeks compared with 25% reduction after either monotherapies. Our findings offer new opportunities for the clinical translation of PDT and irinotecan combination therapy for effective pancreatic cancer treatment.
Assuntos
Antineoplásicos Fitogênicos/farmacologia , Antineoplásicos Fitogênicos/uso terapêutico , Camptotecina/análogos & derivados , Neoplasias Pancreáticas/tratamento farmacológico , Fotoquimioterapia , Membro 2 da Subfamília G de Transportadores de Cassetes de Ligação de ATP , Transportadores de Cassetes de Ligação de ATP/fisiologia , Animais , Camptotecina/administração & dosagem , Camptotecina/farmacocinética , Camptotecina/uso terapêutico , Estabilidade de Medicamentos , Humanos , Proteínas Inibidoras de Apoptose/antagonistas & inibidores , Irinotecano , Lipossomos , Masculino , Camundongos , Transportadores de Ácidos Monocarboxílicos/análise , Transportadores de Ácidos Monocarboxílicos/genética , Proteínas Musculares/análise , Proteínas Musculares/genética , Nanopartículas , Proteínas de Neoplasias/fisiologia , Neoplasias Pancreáticas/irrigação sanguínea , Neoplasias Pancreáticas/mortalidade , Neoplasias Pancreáticas/patologia , Porfirinas/química , Survivina , Resultado do TratamentoRESUMO
Drug-resistant micrometastases that escape standard therapies often go undetected until the emergence of lethal recurrent disease. Here, we show that it is possible to treat microscopic tumors selectively using an activatable immunoconjugate. The immunoconjugate is composed of self-quenching, near-infrared chromophores loaded onto a cancer cell-targeting antibody. Chromophore phototoxicity and fluorescence are activated by lysosomal proteolysis, and light, after cancer cell internalization, enabling tumor-confined photocytotoxicity and resolution of individual micrometastases. This unique approach not only introduces a therapeutic strategy to help destroy residual drug-resistant cells but also provides a sensitive imaging method to monitor micrometastatic disease in common sites of recurrence. Using fluorescence microendoscopy to monitor immunoconjugate activation and micrometastatic disease, we demonstrate these concepts of "tumor-targeted, activatable photoimmunotherapy" in a mouse model of peritoneal carcinomatosis. By introducing targeted activation to enhance tumor selectively in complex anatomical sites, this study offers prospects for catching early recurrent micrometastases and for treating occult disease.
Assuntos
Sistemas de Liberação de Medicamentos/métodos , Imunoconjugados/uso terapêutico , Monitorização Imunológica/métodos , Micrometástase de Neoplasia/diagnóstico , Micrometástase de Neoplasia/tratamento farmacológico , Neoplasias Ovarianas/patologia , Animais , Anticorpos Monoclonais , Endoscopia/métodos , Feminino , Fluorescência , Imunoterapia/métodos , Luz , Camundongos , Micrometástase de Neoplasia/imunologia , Fototerapia/métodos , Sensibilidade e EspecificidadeRESUMO
The effect of the alkyl side chain length of coenzyme Q10 on mitochondrial respiratory chain function has been investigated by the use of synthetic ubiquinone derivatives. Three analogues (3, 4 and 6) were identified that exhibited significantly improved effects on mitochondrial oxygen consumption and mitochondrial membrane potential, and also conferred significant cytoprotection on cultured mammalian cells in which glutathione had been depleted by treatment with diethyl maleate. The analogues also exhibited lesser inhibition of the electron transport chain than idebenone. The results obtained provide guidance for the design of CoQ10 analogues with improved activity compared to that of idebenone (1), the latter of which is undergoing evaluation in the clinic as a therapeutic agent.
Assuntos
Transporte de Elétrons/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Ubiquinona/análogos & derivados , Animais , Bovinos , Linhagem Celular , Linhagem Celular Tumoral , Citoproteção , Transporte de Elétrons/fisiologia , Humanos , Leucemia/metabolismo , Leucemia/patologia , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Mitocôndrias/metabolismo , Consumo de Oxigênio/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Células Ganglionares da Retina/citologia , Células Ganglionares da Retina/efeitos dos fármacos , Células Ganglionares da Retina/metabolismo , Relação Estrutura-Atividade , Ubiquinona/química , Ubiquinona/metabolismo , Ubiquinona/farmacologiaRESUMO
Two new aza analogues of the neuroprotective agent idebenone have been synthesized and characterized. Their antioxidant activity, and ability to augment ATP levels have been evaluated in several different cell lines having suboptimal mitochondrial function. Both compounds were found to be good ROS scavengers, and to protect the cells from oxidative stress induced by glutathione depletion. The compounds were more effective than idebenone in neurodegenerative disease cells. These novel pyrimidinol derivatives were also shown to augment ATP levels in coenzyme Q(10)-deficient human lymphocytes. The more lipophilic side chains attached to the pyrimidinol redox core in these compounds resulted in less inhibition of the electron transport chain and improved antioxidant activity.
Assuntos
Antioxidantes/química , Mitocôndrias/metabolismo , Fármacos Neuroprotetores/química , Pirimidinas/química , Ubiquinona/análogos & derivados , Trifosfato de Adenosina/metabolismo , Animais , Antioxidantes/síntese química , Antioxidantes/toxicidade , Bovinos , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Desenho de Fármacos , Glutationa/metabolismo , Humanos , Linfócitos/efeitos dos fármacos , Linfócitos/metabolismo , Mitocôndrias/enzimologia , Complexos Multienzimáticos/antagonistas & inibidores , Complexos Multienzimáticos/metabolismo , NADH NADPH Oxirredutases/antagonistas & inibidores , NADH NADPH Oxirredutases/metabolismo , Doenças Neurodegenerativas/metabolismo , Doenças Neurodegenerativas/patologia , Fármacos Neuroprotetores/síntese química , Fármacos Neuroprotetores/toxicidade , Pirimidinas/síntese química , Pirimidinas/toxicidade , Espécies Reativas de Oxigênio/metabolismo , Ubiquinona/síntese química , Ubiquinona/química , Ubiquinona/genética , Ubiquinona/metabolismo , Ubiquinona/toxicidadeRESUMO
Selected pyridinol analogues of the experimental neuroprotective drug idebenone have been synthesized and evaluated as antioxidants capable of preserving mitochondrial function. The compounds, having a different redox core but the same side chain as idebenone, exhibited a range of potencies, reflecting differences in their structures. The results obtained provide guidance in the design of such analogues with improved properties. Analogues were identified that have significantly improved antioxidant activity compared with idebenone in cultured lymphocytes, and which exhibit lesser inhibition of the electron transport chain.
Assuntos
Antioxidantes/farmacologia , Citoproteção/efeitos dos fármacos , Mitocôndrias Cardíacas/efeitos dos fármacos , Piridonas/farmacologia , Animais , Antioxidantes/síntese química , Antioxidantes/química , Bovinos , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Humanos , Peroxidação de Lipídeos/efeitos dos fármacos , Linfócitos/efeitos dos fármacos , Linfócitos/metabolismo , Mitocôndrias Cardíacas/enzimologia , Mitocôndrias Cardíacas/metabolismo , Membranas Mitocondriais/efeitos dos fármacos , Membranas Mitocondriais/metabolismo , Estrutura Molecular , Complexos Multienzimáticos/antagonistas & inibidores , Complexos Multienzimáticos/metabolismo , NADH NADPH Oxirredutases/antagonistas & inibidores , NADH NADPH Oxirredutases/metabolismo , Piridonas/síntese química , Piridonas/química , Espécies Reativas de Oxigênio/antagonistas & inibidores , Espécies Reativas de Oxigênio/metabolismo , Relação Estrutura-Atividade , Células Tumorais CultivadasRESUMO
PURPOSE: We evaluated the efficacy and safety of photochemical corneal stiffening by palladium bacteriochlorin 13'-(2-sulfoethyl)amide dipotassium salt (WST11) and near infrared (NIR) illumination, using ex vivo and in vivo rabbit eye models. METHODS: Corneas of post mortem rabbits and living rabbits were pretreated topically with 2.5 mg/mL WST11 in saline or in 20% dextran T-500 (WST-D), washed and illuminated with an NIR diode laser (755 nm, 10 mW/cm(2). Studies with corneas of untreated fellow eyes served as controls. Tensile strength measurements, histopathology, electron spin resonance, and optical spectroscopy and fluorescence microscopy were used to assess treatment effects. Comparative studies were performed with standard riboflavin/ultraviolet-A light (UVA) treatment. RESULTS: WST11/NIR treatment significantly increased corneal stiffness following ex vivo or in vivo treatment, compared to untreated contralateral eyes. The incremental ultimate stress and Young's modulus of treated corneas increased by 45, 113, 115%, and 10, 79, and 174% following 10, 20, and 30 minutes of incubation with WST11, respectively. WST-D/NIR had a similar stiffening effect, but markedly reduced post-treatment edema and shorter time of epithelial healing. WST11/NIR and WST-D/NIR generate hydroxyl and superoxide radicals, but no singlet oxygen in the cornea. Histology demonstrated a reduction in the keratocyte population in the anterior half of the corneal stroma, without damage to the endothelium. CONCLUSIONS: Treatment of rabbit corneas, with either WST11/NIR or WST-D/NIR, increases their biomechanical strength through a mechanism that does not involve singlet oxygen. The WST-D/NIR treatment showed less adverse effects, demonstrating a new potential for clinical use in keratoconus and corneal ectasia after refractive surgery.
Assuntos
Bacterioclorofilas/farmacologia , Córnea , Fototerapia/métodos , Resistência à Tração/efeitos dos fármacos , Resistência à Tração/efeitos da radiação , Animais , Bacterioclorofilas/farmacocinética , Fenômenos Biomecânicos/efeitos dos fármacos , Fenômenos Biomecânicos/fisiologia , Córnea/efeitos dos fármacos , Córnea/fisiologia , Córnea/efeitos da radiação , Ceratócitos da Córnea/efeitos dos fármacos , Ceratócitos da Córnea/fisiologia , Ceratócitos da Córnea/efeitos da radiação , Substância Própria/efeitos dos fármacos , Substância Própria/fisiologia , Substância Própria/efeitos da radiação , Espectroscopia de Ressonância de Spin Eletrônica , Endotélio Corneano/efeitos dos fármacos , Endotélio Corneano/fisiologia , Endotélio Corneano/efeitos da radiação , Raios Infravermelhos/uso terapêutico , Lasers Semicondutores , Modelos Animais , Fotodegradação/efeitos dos fármacos , Fármacos Fotossensibilizantes/farmacologia , Coelhos , Espectrometria de Fluorescência , Estresse Mecânico , Resistência à Tração/fisiologiaRESUMO
An aza analogue (1) of the experimental neuroprotective drug idebenone has been prepared and evaluated. The compound quenches lipid peroxidation more effectively than α-tocopherol and potently suppresses reactive oxygen species in cells under oxidative stress. It is thought to do so via a catalytic cycle in which both forms of oxidative stress are suppressed simultaneously. Consequently, the compound effectively protects cultured CEM leukemia cells and Friedreich's ataxia fibroblasts from oxidative stress more effectively than idebenone or idebenol.
RESUMO
Light-induced radical generation is the hallmark of fundamental processes and many applications including photosynthesis and photodynamic therapy (PDT). In this manuscript, we present two novel observations made upon monitoring light-induced generation of reactive oxygen species (ROS) in aqueous solutions by WST11, a water-soluble derivative of the photosynthetic pigment Bacteriochlorophyll a (Bchl). Using a host of complementary experimental techniques including time-resolved spectroscopy at the subpicosecond to the millisecond range, ESR spectroscopy, electrochemistry, spectroelectrochemistry, oximetry, and protein mass spectroscopy, we first show that in aqueous solutions WST11 generates only superoxide (O(2)(-*)) and hydroxyl (OH*) radicals with no detectable traces of singlet oxygen. Second, we show that WST11 makes a noncovalent complex with human serum albumin (HSA) and that this complex functions as a photocatalytic oxidoreductase at biologically relevant concentrations enabling approximately 15 cycles of electron transfer from the associated HSA protein to molecular oxygen in the solution. These findings rule out the paradigm that porphyrin and chlorophyll based PDT is mainly mediated by formation of singlet oxygen, particularly in vascular targeted photodynamic therapy (VTP) with sensitizers that undergo photoactivation during circulation in the plasma, like [Pd]-Bacteriopheophorbide (WST09, Tookad). At the same time, our findings open the way for new design paradigms of novel sensitizers, since O(2)(-*) and OH* radicals are well-recognized precursors of important pathophysiological processes that can be activated for achieving tumor eradication. Moreover, the finding that promiscuous protein scaffolds become sinks for holes and electrons when holding light-activated pigments provides a new insight to the evolution and action mechanism of natural light activated oxidoreductases (such as photosynthetic reaction centers) and new guidelines for the preparation of synthetic-light converting machineries.